Reformatted from the 2000 Report of the AVMA Panel on Euthanasia –

Carbon monoxide

"Carbon monoxide used for individual animal or mass euthanasia is acceptable for dogs, cats, and other small mammals, provided that commercially compressed CO is used and the following precautions are taken:

"(1) personnel using CO must be instructed thoroughly in its use and must understand its hazards and limitations;

"(2) the CO chamber must be of the highest quality construction and should allow for separation of individual animals;

"(3) the CO source and chamber must be located in a well-ventilated environment, preferably out of doors;

"(4) the chamber must be well lit and have view ports that allow personnel direct observation of animals;

"(5) the CO flow rate should be adequate to rapidly achieve a uniform CO concentration of at least 6% after animals are placed in the chamber, although some species (eg, neonatal pigs) are less likely to become agitated with a gradual rise in CO concentration; and

"(6) if the chamber is inside a room, CO monitors must be placed in the room to warn personnel of hazardous concentrations. It is essential that CO use be in compliance with state and federal occupational health and safety regulations."